It’s called Erythema Migrans, doesn’t itch or hurt. It’s the only manifestation of Early Lyme Disease, which occurs 1-2 weeks after the tick bite (maximum 1 month). Blood tests then are usually still negative, and treatment always works. See Lyme Disease.
The rash usually begins as a red spot that enlarges. The center may be dark red, and often eventually turn clear (it’s often called a “bull’s eye” rash). There are lots of variations, especially on dark skin. Here are some examples.